1. Field of the Invention
It is often desirable to increase the resolution of an image. For example, certain imagers, such as terahertz (THz), infrared (IR) or low cost imagers may capture low-resolution images. By increasing the resolution of one or more of the low-resolution images, the image quality can be improved.
A super-resolution image may be reconstructed from a plurality of low-resolution images of a same scene. For example, the images may correspond to a sequence of frames of a video stream captured by an imager. By combining the visual information from multiple images, the total amount of visual information can be increased in the super-resolution image. Indeed, because each low-resolution image is in some way different from the others, it contributes some unique information that is absent from the other images.
A method of generating a super resolution image based on multiple low-resolution images generally involves up-scaling one of the low-resolution images, and then modifying the pixel values of the up-scaled image based on pixel values taken from the low-resolution images.
However, there is a technical problem in accurately selecting the pixel values to be used for this pixel modification. Indeed, the selected pixel values should correspond to pixels having positions in their respective images that accurately match the position of the pixel to be adjusted. Any miss-match between the pixel positions will result in added noise and thus a reduced image quality.
One technique that has been proposed for matching the pixel positions is to estimate the motion of objects from the differences between the low-resolution images. However, such motion estimation is difficult and complex to perform, and can be imprecise, particularly in the case of objects that make non-continuous or non-uniform movements.
US patent application N°US2009/0110285 describes a method of super-resolution image reconstruction that does not rely on motion estimation directly. Instead, the method compares pixel values of pixels surrounding a target pixel with pixel values of pixels surrounding pixels in the target pixel's neighborhood in neighboring images.
While the technique described in this US patent application provides an alternative to performing motion estimation, it has a number a drawbacks, for example in terms of complexity, and the resulting image quality.
There is thus a need in the art for an improved method and device for performing high-resolution image reconstruction.
2. Description of the Related Art
The present disclosure relates to a method and device for performing super-resolution image reconstruction, and in particular to a method and device for generating a super-resolution image from one or more low-resolution images.